Selective Extraction of Antioxidants by Formation of a Deep Eutectic Mixture through Mechanical Mixing

Abstract

Extraction of active compounds from natural materials is commonly used to produce a diverse range of ingredients, nutrients, drugs, flavors, and fragrances. While solventbased approaches are standard for these extraction procedures, large solvent volumes, greenhouse gas emission (due to atmospheric release of volatile organic compounds), and large energy requirements are significant issues. Here, we describe a novel process wherein a mechanical action is applied to a solid-state mixture comprising a quaternary ammonium salt and a biological material containing active molecules to form a deep eutectic mixture. It is first shown that eutectic mixtures can be formed for a wide range of naturally occurring compounds. Selective extraction of these compounds from natural products is then demonstrated using rosemary leaves with three different quaternary ammonium salts. The eutectic mixture formed is purified by liquid/liquid extraction using an oily phase to concentrate the active constituents in the deep eutectic phase. The resulting natural extracts are shown to exhibit high antioxidant activities, which were measured using the conjugated autoxidizable triene (CAT) and the oxygen radical absorbance capacity (ORAC) assays.

Green and highly effective extraction of bioactive flavonoids from Fructus aurantii employing deep eutectic solvents-based ultrasonic-assisted extraction protocol

“…In comparison with conventional organic solvents, DESs are not only non-toxicity, inexpensive in cost, environmental friendliness, biodegradable, nonflammable and stable, but they also have a series of benefits including quick and easy synthesis, availability and high-efficiency [16] , [17] , [18] , [19] , [20] , [21] , [22] . Hence, these unique characteristics make them preferable over the conventional solvents used in extraction procedures [13] , [23] , [24] , [25] , [26] , [27] . Among them, sustainable, eco-friendly, and non-hazardous choline chloride-based DESs represent the most recent and ecologically suitable substitutes for traditional organic solvents [26] .…”

A Perspective on Missing Aspects in Ongoing Purification Research towards Melissa officinalis

“…Uncommon selectivity, compared to organic solvents, can be obtained through the "tuning" of extracts' properties using DESs tailored to specific applications [96]. The latest development in this field relates to the ifcastron-situ formation of DESs, assisted by mechanical mixing (a mechano-chemical approach) [97]. In this process, only one of the pre-defined DES components in solid state is mixed with powdered plant material.…”